In ATM communications networks, information is transmitted in the form of packets or cells according to an asynchronous transmission mode (Asynchronous Transfer Mode, ATM). In these ATM networks, jitter of the ATM cells occurs, dictated by the system, during the transmission operation. Jitter is generally produced by buffering of the ATM cells, which is carried out in a network node, and depends on a number of parameters. Thus, for example, the number of nodes in the network, the loading (that is to say how many bits/s are transmitted) and the nature of the traffic (that is to say whether a variable bit rate is transmitted) have a direct influence on the jitter magnitude. The jitter of an ATM cell thus fluctuates between 0 (optimum value, in other words no jitter) and a maximum value. The occurrence of jitter is particularly disadvantageous when the transmitted information takes the form of video signals or voice signals.
Limit values have been specified in the past for the purpose of avoiding excessively high jitter. Thus, for example in accordance with a specification made by the Federal German Post Office, the maximum jitter per network node must not exceed a value of 250 .mu.s. In the case of a connection in which 6 network nodes are traversed (typical value for a national connection), the maximum jitter can consequently amount to up to 1.5 ms. If a transmission bit rate of 4 Mbit/s (corresponding to a rate of 10000 cells/s) is taken as a basis, this means that, in the extreme case, instead of 15 ATM cells, not a single ATM cell arrives in the receiving device.
German Patent Specification DE 41 32 518 C2 discloses a circuit arrangement for the transmission of digital message signals via a broadband communications system operating according to the asynchronous transfer mode. Said document discloses how the effects of jitter in a receiving device can be reduced. This is done by self-synchronization of buffer memory devices, which proves to be complicated in practice.